Electrical relay



May 14, 1929. w. B. WELLS 1 ELECTRICAL RELAY Filed OOL. 27, 1926 INVENTOR'. 'Uff WM,

@fm1/M2 fr0/,.7 E d L L J 5 1 OQU B 1 Patented May 14, 1929.

UNITED STATES PATENT OFFICE.

WESLEY B. WELLS, OF ILKINSBURG. PENNSYLVAN., ASSGNOR TO THE UNION SWITCH & SIGNAL COMPNY, OF SVJISSVJRLE, PENNSYLVANIL, A CORPORATION OF PENNSYLVANIA.

ELECTRICAL RELAY.

Application filed October' 2'?, N26.

My invention relates to electrical relays.

will describe one form of electrical relay enibodying my invention, and will then point out the novel featiiires thereof in claims.

In the acconipanying drawing, Fig. l is a vertical longitudinal sectional View showing one form of electrical relay embodying my invention. F ig. Q. is a vertical sectional view along theline 11-11 in l.

Similar reference characters refer to similar parts in both views. y

Referring to the drawing, the relay comprises a top plate B of non-magnetizable material and a cover glass A. rlhe top plate B is provided with an opening P1 over which is fitted a. terminal board C of insulating` material carrying a plurality of binding pests L for the purpose of connecting the relay with exterior circuits. Two magnetizablc pole pieces D, D, terminating on the underside of the top plate Bin pole faces D1, D1 are provided with upstanding, parallel legs D2. lt will be seen from the drawing that the pole faces D1 of the pole pieces D are spaced apart on the underside of the top plate. An` armature G bridging the pole faces Dl is attached to a rocker arm F which is pivotally supported by trunnion screws .7, 7 in a bracket E attached to the underside of the top plate.

Magnetic flux is supplied to the pole pieces D by a magnet M having a magnetizable core P extending transversely across the upstanding legs D2 of the pole pieces D. The terminals of the magnet M are connected to certain of the binding posts L and the supply of current to this magnet may be controlled in any suitable manner. When the magnet M is energized, magnetic flux from the magnet flows through the magnetic circuit including the core P and two pole pieces D and the armature G.

The armature G controls contact mechanism comprising a movable finger H canned by the rocker arm F, but insulated therefrom by an insulating pillar T. The finger l-l cooperates with a front Contact J and a back contact K so that when the relay is energized armature G is swung upwardly toward the pole faces D1, thereby moving finger H into engagement with front contact fl. When the relay is deenergized, however, the armature G drops away from the pole faces D1 and allows finger H to engage back contact K.

Under certain conditions, it is desirable te Serial No. 144,490.

vary the Values of the currents upon which the relay will piclr up and release. In my invention I prefer to accomplish this result by varying the position of the magnetic core P with respect to the pole pieces D, thereby varying the length of the air gaps between these members. The resulting Variation in the reluctance of the magnetic circuit supplied with flax by the magnet M provides a means for varying the current required in magnet lvl to piel-1 up the arn'iature G. As shown in the drawing, each end of the core P extends outwardly beyond the associated pole piece D and is provided. with a screw R which passes freely through a hole in the end of the core and is threaded in the top plate B. A coil spring Q, is fitted on each of the screws l?. between the core P and the top plate B. These coil springs constantly urge the core upwardly, forcing the core against the heads of the screws R. lt follows that by turning down the screws R, the core P may be drawn closer to the pole pieces D against the force exert-ed by the springs Q. Gn the other hand, when the screws R are turned in such direction as to raise the heads of the screws the springs Q lift the core P away from the pele pieces D.

In order to clamp the screws lt in their adjusted posit-ions, each of the screws is provided with a locking clip S comprising` a flat plate il provided with a hole to receive the associated screw R, which is placed between the core P and the associated spring Q. Each clip S also comprises an upstanding leaf 1 provided with a vertically disposed slet- 2 and two lugs 3 arranged to engage the sides of the core P. The parts are so proportioned that the leaf l bears against the side of the head of the associated screw R with sullicient pressure to prevent accidental displacement ofthe screw. The purpose of the slot 2 in the leaf l of each of the clips S is to permit the clip to lock the screw by engaging a corner of the screw head as well as by engaging the flat face of the screw head. This arrangement permits twice the number of locking positions as there are sides to the screw head. That is to say, with the usual form of hexagonal head machine screw, the locking clip permits the screw to be clamped in any one of twelve po sitions for each turn of the screw. It will be seen that with relays embodying my invention, by making the thread of the screws R Cil very fine, variations in the position of the core with respect to the pole pieces D may be made in extremely .small steps.

ln order to prevent displacement. of the magnet M upon the core and to facilitate adustnient of the core with respect to the pole pieces, the magnet is provided7 at its ends, with two bobbin heads 5, fi, each provided with two spaced vertical slu'uilders 6 delining a grom'e which receives apole piece D.

Unc advantage possessed by relays constructed in accordance with my invention over those heretofore known is that a single rclay provided with only one magnet may be simply and conveniently adjusted to pick up and release for any reasonable values of current. Another advantage is that after the relay has once been properly adjusted, by manipulation of the screws R, for one set of pickup and release values, the locking clips S prevent accidental displacement of the mem )ers and maintain the device in its adjusted position indefinitely.

Relays embodying my invention are particularly adapted for, though in no way limited to, use in railway trafiie controlling systems. The relays may be used7 for example.v as approach lighting relays and light-out relays in signaling systems7 and as repeater relays and checking relays in train controlling systems.

Although I have herein shown and described only one form of electrical relay embodying my invention, it is understood that vaious changes and modiications may be made therein within the scope of the appendable armature bridgingr the pole faces, a single electromagnet having a magnetizable core passing therethrough and bridging the free ends of the pole pieces, means for constantly urging said core and magnet as a whole away trom the pole pieces, and adj ust:- able clamping means for drawing the core and magnet as a whole toward the pole pieces against the bias of said means.

2. A relay comprising a non-magnet-izable top plate, two magnetizable pole pieces terminating in spaced pole pieces on the underside of the plate, and also having legs extending upwardly from said plate, contact mechanism comprising a movable armature bridging the pole faces, a single electromagnet having a magnetizable core passing therethrough and bridging the legs of the pole pieces, a screw passing through a hole in the core and threaded in the top plate for adjusting the position of said core and magnet as a whole with respect to one of said cores, and a compression spring between the top plate and the core for biasing said core and magnet ad a whole away from such core.

3. A relay comprising a top plate having two pole pieces projecting therethrough in spaced relation, contact mechanism including a movable armature bridging the pole pieces, an eleetromagnet provided with a core passing therethrough and extending over the pole pieces, two screws passing through said core on opposite sides of the magnet respectively and bot-h threaded in the top plate, and two coil springs one on each screw between the top plate and the core for urging the core against Athe head of the associated screw whereby rotation of either screw varies the air gap between the adjacent end of the core and the adjacent pole piece.

In testimony whereof I aftix my signature.

WESLEY B. WELLS. 

